Replaceable cover for bars in a printing system

ABSTRACT

A bar for a web transport system in a printing system can include a first set of pins extending outward from an exterior surface of the bar and a replaceable cover wrapped over at least a portion of an exterior surface of the bar. The replaceable cover includes a plurality of openings at one end of the cover with at least a portion of the openings positioned at the locations of respective pins. Fasteners attached at another end of the cover are adapted to removably attach the cover over the bar.

TECHNICAL FIELD

The present invention generally relates to printing systems and more particularly to bars suitable for use in printing systems and methods for transporting the web. Still more particularly, the present invention relates to a removable replaceable cover for bars in a printing system.

BACKGROUND

Continuous web printing allows economical, high-speed, high-volume print reproduction. In this type of printing, a continuous web, such as print media (e.g., paper) or a support mechanism in which the print media is disposed over, is fed past one or more printing subsystems or modules that form images by applying one or more colorants onto the surface of the print media. Various components within a printing system are used to create tension in the web so that the web does not shift in the in-track (the direction of movement) and cross-track directions as the web moves through the printing system. The tension is also used to inhibit fluttering (up or down motion) as the web travels through the printing system.

Some of the components used to produce and adjust the tension in the web or to transport the web through a printing system are stationary bars placed at different locations within the printing system. Stationary bars include turnbars and S-wraps. Turnbars are frequently used to change the direction of the web, or as a pair to flip over the print media, while S-wraps are used to produce tension in the web. The stationary bars have curved surfaces that the web slides over during transport. As the web is pulled over these surfaces, the friction of the web across these surfaces produces tension in the web.

Some bars are “static” in which the web runs directly on the bar. For turnbar applications, a cover material is typically applied over the contact surface to reduce drag from the web. Generally, this cover material is adhered with adhesive directly onto the exterior surface of the bars. The cover material must be applied smoothly, with no wrinkles or bubbles that could adversely affect web tracking.

Typically, the web travels through the printing system at a high rate of speed. By way of example only, the web can travel six hundred to one thousand feet per minute. Over time, the combination of the high speed and the friction of the web produce heat and wear on the low-friction cover material on the exterior surfaces of the bars. The cover material can wear to the point of causing web handling problems. Since the cover material is adhered directly to the bars, it can be difficult and time consuming to replace the material. When the wear reaches an unacceptable level, the bars are removed from the printing system and either the cover material re-conditioned or the bar is replaced entirely. Replacing the bars can take several hours, during which time the printing system is shut down. Moreover, the alignment of the web in the printing system must be re-calibrated once the bars have been replaced. These actions increase the cost of a print job and reduce the throughput of the printing system.

SUMMARY

According to one aspect, a stationary bar for a printing system includes a first set of pins extending outward from an exterior surface of the bar and a removable cover wrapped over at least a portion of the exterior surface of the bar. The removable cover includes a first set of openings at one end of the removable cover. Openings in the first set of openings are positioned at locations of respective pins so that a pin can be inserted into an opening. Fasteners are adapted to removably attach the cover over the bar. By way of example only, the bar can be configured as a turnbar for a turnover module or a bar in an S-wrap device.

According to another aspect, a second set of openings can be at the other end of the cover. A fastener can be connected or attached to a respective opening in the second set of openings. A fastener can be adapted to removably attach to a respective pin in the first set of pins.

According to another aspect, the bar can include a second set of pins extending outward from the exterior surface of the bar and positioned a given distance away from the first set of pins.

According to another aspect, the bar can include a hollow center and holes can be formed through the bar. Pressurized air or gas can then be emitted from the holes. Holes can be formed through the removable cover. The locations of the holes through the removable cover can correspond to all of the locations of the holes formed through the bar. Alternatively, the locations of the holes through the removable cover can correspond to only a portion of the locations of the holes formed through the bar.

According to another aspect, a web transport system in a printing system can include bars for supporting a moving web, where the web can be the print media or a support mechanism in which the print media is disposed over. A first set of pins extend outward from an exterior surface of at least one stationary bar. A removable cover can be wrapped over at least a portion of the exterior surface of the at least one bar. The removable cover can include a first set of openings at one end of the cover. Openings in the first set of openings are positioned at locations of respective pins so that a pin can be inserted into an opening. Fasteners located at another end of the cover are adapted to removably attach the cover over the bar. By way of example only, the bar can be configured as a turnbar for a turnover module or a bar in an S-wrap device.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are better understood with reference to the following drawings. The elements of the drawings are not necessarily to scale relative to each other. Like numbers indicate like parts throughout the views.

FIG. 1 is a schematic side view of one example of a continuous web printing system in an embodiment in accordance with the present invention;

FIG. 2 illustrates a top perspective view of one example of a turnover module suitable for use in printing system 100 in an embodiment in accordance with the invention;

FIG. 3 is another top perspective view of the turnover module 116 shown in FIG. 2;

FIG. 4 illustrates the path of the print media through the turnover module 116 in an embodiment in accordance with the invention;

FIG. 5 depicts one example of a stationary turnbar and replaceable cover suitable for use in a turnover module in an embodiment in accordance with the invention;

FIGS. 6-7 illustrate the fastening system 512 shown in FIG. 5;

FIG. 8 depicts the stationary turnbar and replaceable cover shown in FIGS. 5-7 in a turnover module in an embodiment in accordance with the invention;

FIG. 9 illustrates another example of a stationary turnbar and replaceable cover suitable for use in a turnover module in an embodiment in accordance with the invention;

FIG. 10 depicts another example of a stationary turnbar suitable for use in a turnover module in an embodiment in accordance with the invention;

FIG. 11 illustrates the stationary turnbar shown in FIG. 10 and a print media in an embodiment in accordance with the invention;

FIG. 12 depicts a replaceable cover suitable for use with the turnbar 1000 shown in FIG. 10 in an embodiment in accordance with the invention; and

FIGS. 13 and 14 depict one example of an S-wrap device and replaceable covers in an embodiment in accordance with the invention.

DETAILED DESCRIPTION

Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The meaning of “a,” “an,” and “the” includes plural reference, the meaning of “in” includes “in” and “on.” Additionally, directional terms such as “on”, “over”, “top”, “bottom”, “left”, “right” are used with reference to the orientation of the Figure(s) being described. Because components of embodiments of the present invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration only and is in no way limiting.

The present description will be directed in particular to elements forming part of, or cooperating more directly with, an apparatus in accordance with the present invention. It is to be understood that elements not specifically shown, labeled, or described can take various forms well known to those skilled in the art. In the following description and drawings, identical reference numerals have been used, where possible, to designate identical elements. It is to be understood that elements and components can be referred to in singular or plural form, as appropriate, without limiting the scope of the invention.

The example embodiments of the present invention are illustrated schematically and not to scale for the sake of clarity. One of ordinary skill in the art will be able to readily determine the specific size and interconnections of the elements of the example embodiments of the present invention.

As described herein, the example embodiments of the present invention apply to bars that support a moving web as the web is transported through a printing system. The web can be the print media or a support mechanism that is routed through the printing system. Inkjet printing is commonly used for printing on paper, where paper is the print media. However, there are numerous other materials in which inkjet is appropriate. For example, vinyl sheets, plastic sheets, textiles, paperboard, and corrugated cardboard can comprise the print media. Additionally, although the term inkjet is often used to describe the printing process, the term jetting is also appropriate wherever ink or other liquids is applied in a consistent, metered fashion, particularly if the desired result is a thin layer or coating.

However, many other applications are emerging which use inkjet printheads to emit liquids (other than inks) that need to be finely metered and deposited with high spatial precision. Such liquids include inks, both water based and solvent based, that include one or more dyes or pigments. These liquids also include various substrate coatings and treatments, various medicinal materials, and functional materials useful for forming, for example, various circuitry components or structural components. As such, as described herein, the terms “liquid” and “ink” refer to any material that is ejected by the printhead or printhead components described below.

Inkjet printing is a non-contact application of an ink to a print media. Typically, one of two types of ink jetting mechanisms are used and are categorized by technology as either drop on demand ink jet (DOD) or continuous ink jet (CIJ). The first technology, “drop-on-demand” (DOD) ink jet printing, provides ink drops that impact upon a recording surface using a pressurization actuator, for example, a thermal, piezoelectric, or electrostatic actuator. One commonly practiced drop-on-demand technology uses thermal actuation to eject ink drops from a nozzle. A heater, located at or near the nozzle, heats the ink sufficiently to boil, forming a vapor bubble that creates enough internal pressure to eject an ink drop. This form of inkjet is commonly termed “thermal ink jet (TIJ).”

The second technology commonly referred to as “continuous” ink jet (CIJ) printing, uses a pressurized ink source to produce a continuous liquid jet stream of ink by forcing ink, under pressure, through a nozzle. The stream of ink is perturbed using a drop forming mechanism such that the liquid jet breaks up into drops of ink in a predictable manner. One continuous printing technology uses thermal stimulation of the liquid jet with a heater to form drops that eventually become print drops and non-print drops. Printing occurs by selectively deflecting one of the print drops and the non-print drops and catching the non-print drops. Various approaches for selectively deflecting drops have been developed including electrostatic deflection, air deflection, and thermal deflection.

Additionally, there are typically two types of web used with inkjet printing systems. The first type is commonly referred to as a continuous web while the second type is commonly referred to as a cut sheet(s). The continuous web refers to a continuous strip of print media, generally originating from a source roll. The continuous web is moved relative to the inkjet printing system components via a web transport system, which typically include drive rollers, web guide rollers, and web tension sensors. Cut sheets refer to individual sheets of print media that are moved relative to the inkjet printing system components via a support mechanism (e.g., rollers and drive wheels or via a conveyor belt system) that is routed through the inkjet printing system.

The invention described herein is applicable to both types of printing technologies. As such, the term web, as used herein, is intended to be generic and not as specific to either type of web or the way in which the web is moved through the printing system.

The terms “upstream” and “downstream” are terms of art referring to relative positions along the transport path of the web; points on the transport path move from upstream to downstream. In FIG. 1 the print media moves from left to right as indicated by feed direction arrow 114. Where they are used, terms such as “first”, “second”, and so on, do not necessarily denote any ordinal or priority relation, but are simply used to more clearly distinguish one element from another.

Referring now to the schematic side view of FIG. 1, there is shown one example of a continuous web printing system in an embodiment in accordance with the invention. Printing system 100 includes a first printing module 102 and a second printing module 104, each of which includes lineheads 106, dryers 108, and a quality control sensor 110. Each linehead 106 typically includes multiple printheads (not shown) that apply ink or another liquid to the surface of the continuous web of print media 112 that is adjacent to the printheads. For descriptive purposes only, the lineheads 106 are labeled a first linehead 106-1, a second linehead 106-2, a third linehead 106-3, and a fourth linehead 106-4. In the illustrated embodiment, each linehead 106-1, 106-2, 106-3, 106-4 applies a different colored ink to the surface of the print media 112 that is adjacent to the lineheads. By way of example only, linehead 106-1 applies cyan colored ink, linehead 106-2 magenta colored ink, linehead 106-3 yellow colored ink, and linehead 106-4 black colored ink.

The first printing module 102 and the second printing module 104 also include a web tension system that serves to physically move the print media 112 through the printing system 100 in the feed direction 114 (left to right as shown in the figure). The print media 112 enters the first printing module 102 from a source roll (not shown) and the linehead(s) 106 of the first module applies ink to one side of the print media 112. As the print media 112 feeds into the second printing module 104, a turnover module 116 is adapted to invert or turn over the print media 112 so that the linehead(s) 106 of the second printing module 104 can apply ink to the other side of the print media 112. The print media 112 then exits the second printing module 104 and is collected by a print media receiving unit (not shown).

First printing module 102 has a support structure that includes a cross-track positioning mechanism (A) for positioning the continuously moving web of print media in the cross-track direction, that is, orthogonal to the direction of travel and in the plane of travel. In one embodiment, cross-track positioning mechanism (A) is an edge guide for registering an edge of the moving media. An S-wrap device (SW), affixed to the support structure of first module 102, includes structure that sets the tension of the print media.

Downstream from the first printing module 102 along the path of the print media 112, the second printing module 104 also has a support structure similar to the support structure for first printing module 102. Affixed to the support structure of either or both the first or second module is a kinematic connection mechanism that maintains the kinematic dynamics of the print media 112 in traveling from the first printing module 102 into the second printing module 104. Also affixed to the support structure of either the first or second module are one or more angular constraint structures for setting an angular trajectory of the print media 112.

Table 1 that follows identifies the lettered components used for print media transport as shown in FIG. 1. An edge guide in which the print media 112 is pushed laterally so that an edge of the media contacts a stop is provided at (A). The slack print media entering the edge guide allows the print media 112 to be shifted laterally without interference and without being over-constrained. The S-wrap device (SW) provides stationary curved surfaces over which the continuous print media 112 slides during transport. As the print media 112 is pulled over these surfaces, the friction of the print media 112 across these surfaces produces tension in the print media. In one embodiment, the S-wrap device (SW) is adapted to adjust the positional relationship between surfaces, to control the angle of wrap and to allow adjustments in the tension of the print media.

TABLE 1 Roller Listing for FIG. 1 Media Handling Component Type of Component A Lateral Constraint (edge guide) SW S-wrap device B In-Feed Drive Roller C Castered and Gimbaled Roller D Gimbaled Load Cell E Servo-Castered and Gimbaled Roller F Fixed Roller (tach) G Rainbow Rollers (Qty = 17, 8 linehead, 6 dryer, 3 QC) H Servo-Castered and Gimbaled Roller I Gimbaled Roller J First Turnover Mechanism Drive K Second Turnover Mechanism Drive L Castered and Gimbaled Roller M Gimbaled Roller N Gimbaled Load Cell O Servo-Castered and Gimbaled Roller P Fixed Roller (tach) Q Rainbow Rollers (Qty = 17, 8 linehead, 6 dryer, 3 QC) R Servo-Castered and Gimbaled Roller S Out-Feed Drive Roller

The first angular constraint is provided by in-feed drive roller B. This is a fixed roller that cooperates with a drive roller in the turnover module 116 and with an out-feed drive roller N in second printing module 104 in order to move the print media 112 through the printing system 100 with suitable tension in the feed direction 114. The tension provided by the preceding S-wrap device (SW) serves to hold the print media 112 against the in-feed drive roll. Angular constraints at subsequent locations downstream along the print media 112 are provided by rollers that are gimbaled so as not to impose an angular constraint on the next downstream media span.

Although FIG. 1 depicts each printing module with four lineheads 106, three dryers 108, and one quality control sensor 110, embodiments in accordance with the invention are not limited to this construction. A printing system can include any number of lineheads, any number of dryers, and any number of quality control sensors. The printing system can also include a number of other components, including, but not limited to, web cleaners and web tension sensors.

And although the printing system shown in FIG. 1 has the turnover module 116 disposed between the first and second printing modules 102, 104, other printing systems can include the turnover module within one of the printing modules.

The invention will now be described with reference to a stationary turnbar in a turnover module and the stationary bars in an S-wrap device. Embodiments of the invention, however, are not limited to these two types of bars in a web transport system. Those skilled in the art will recognize the invention can be used with other components in a paper transport system. The present invention can be used with any stationary object, commonly referred to as “brush bars”, in the transport path of a printing system.

FIG. 2 illustrates a top perspective view of one example of a turnover module suitable for use in printing system 100 in an embodiment in accordance with the invention. Turnover module 116 includes stationary turnbars 200, 202 positioned at different angles with respect to the input path 204 and the output path 206. Other embodiments in accordance with the invention can include one or more turnbars in a turnover module. For example, one turnbar can be included in a turnover module that redirects the print media ninety degrees. The web is fed directly from the exit of turnbar 200 into a second print module oriented perpendicular to the first print module.

The print media 112 enters along the input path 204 with ink or another liquid jetted onto a front side of the print media 112. In FIGS. 2-4, the front side of the print media is identified as 112 f and the back side of the print media as 112 b.

The print media 112 then wraps around stationary turnbar 200 and passes to unit 208, where the print media wraps around a bar (not show) included in unit 208. The print media 112 then exits unit 208 front side up, as shown in region 210. After exiting unit 208, the print media 112 wraps around stationary turnbar 202 and is directed along the output path 206. The print media 112 is now inverted or turned over (see region 212) and the back side of print media 112 b is positioned to receive ink from the linehead(s) in the next printing module (e.g., printing module 104 in FIG. 1). The print media 112 passes over bar 214 and exits the turnover module 116 along the output path 206.

FIG. 3 is another top perspective view of the turnover module 116 shown in FIG. 2. As discussed earlier, print media 112 wraps around stationary turnbar 200 and then wraps around bar 300 in unit 208. After exiting unit 208, the print media 112 wraps around stationary turnbar 202 and is directed along the output path 206. The print media 112 is inverted or turned over with the back side of print media 112 b positioned to receive ink from the linehead(s) when the print media exits turnover module 116. FIG. 4 illustrates the path of the print media 112 through the turnover module 116 shown in FIGS. 2 and 3.

Referring now to FIG. 5, there is shown one example of a stationary turnbar and replaceable cover suitable for use in a turnover module in an embodiment in accordance with the invention. Tumbar 500 can be mounted on fasteners disposed within a turnover module using mounting brackets 502. Each mounting bracket 502 includes one or more holes 504 that receive a fastener within the turnover module.

Pins 506 extend outward from the exterior surface 508 of turnbar 500. A turnbar can include two or more pins in embodiments in accordance with the invention. The pins are located in positions that will not impede the web as the web slides over the turnbars. Replaceable cover 510 is removably attached around a portion of the exterior surface 508 of the turnbar 500 using fastening systems 512. The replaceable cover 510 is made of a low-friction material in an embodiment in accordance with the invention. The replaceable cover 510 can be made of different types of materials designed specifically for the different types of webs. A press operator can quickly change the replaceable covers between different print jobs.

FIGS. 6-7 more clearly illustrate fastening system 512 in an embodiment in accordance with the invention. Each end of the replaceable cover 510 is wrapped around and affixed to beams 600, 602. Beams 600, 602 extend across the width of the replaceable cover in an embodiment in accordance with the invention. Other embodiments in accordance with the invention can configure one or both beams differently. For example, beam 600 can be formed as a discontinuous collection of pieces with each piece being centered around a pin 506.

The fastening system 512 includes a first set of openings 514 formed through one end of the replaceable cover 510 (including beam 600), a second set of openings 516 formed through the other end of the replaceable cover 510 (including beam 602), and fasteners 518. The location of each opening in the first set of openings 514 correspond to the locations of the pins 506 extending out from the exterior surface 508 of the turnbar 500. Alternatively, the location of only a portion of the openings in the first set of openings 514 correspond to the locations of the pins 506 extending out from the exterior surface 508 of the turnbar 500. The locations of the openings in the first set of openings can correspond to a variety of pin locations found on different turnbars, thereby allowing the cover to be used on different sizes of bars or bars having different pin locations.

One end of each fastener 518 is connected to an opening in the second set of openings 516. The pins 506 are inserted in openings in the first set of openings 514. The second end of each fastener 518 is connected or attached to, or over, a pin 506. Fasteners 518 are springs in an embodiment in accordance with the invention. FIG. 6 shows one end of the spring 518 disconnected from the pin 506 while FIG. 7 depicts the one end of the spring 518 attached to the pin 506.

The fastening system 512 illustrated in FIGS. 5-7 enables a quick and easy replacement of the replaceable cover 510 while the turnbar is mounted in the turnover module. The turnbar does not need to be removed from the turnover module, thereby eliminating the time needed to replace the bar and the time needed to re-align the print media. The fastening system 512 can also compensate for tolerance and thermal expansion.

The fastening system 512 can be implemented differently in other embodiments in accordance with the invention. By way of example only, beams 600, 602 can attach to the exterior surface magnetically. Alternatively, instead of using springs, the fasteners can be configured as box clasps or with screw-like fasteners (with or without the second set of openings 516).

Referring now to FIG. 8, there is shown the turnbar and replaceable cover shown in FIGS. 5-7 in a turnover module in an embodiment in accordance with the invention. Turnover module 800 operates similarly to turnover module 116 described with reference to FIGS. 2-4. Turnbars 500 are positioned at an angle with respect to each other (and with respect to the input and output paths of the web). By way of example only, turnbars 500 can be positioned at a forty-five degree angle with respect to each other. When positioned at a forty-five degree angle, the turnbars 500 can include two sets of pins, with one set of pins used to attach the replaceable cover 510 to the lumbar. Which set of pins is inserted into openings in the first set of openings depends on how the bar is oriented in the turnover module (e.g., like Lumbar 200 or turnbar 202).

FIG. 9 illustrates one example of a turnbar having two sets of pins and a replaceable cover in an embodiment in accordance with the invention. For simplicity, only one fastening system 900 is shown in FIG. 9. Those skilled in the art will recognize that some or all of the fastening systems are configured as the one illustrated fastening system.

Similar to the embodiment shown in FIGS. 5-7, fastening system 900 includes a first set of openings 514 formed through one end of the replaceable cover 510, a second set of openings 516 formed through the other end of the replaceable cover 510, pin 506, and fastener 518. Fastening system 900 also includes a second pin 902. Pins 506 form a first set of pins and pins 902 a second set of pins in the illustrated embodiment. Depending on the orientation of a lumbar in a turnover module, the first set of openings 514 mate with either the first set of pins 506 or the second set of pins 902. The second pin 902 is offset from pin 506 so that fastener 518 can connect or attach to, or over, a respective pin 506 unimpeded.

Referring now to FIG. 10, there is shown another example of a turnbar suitable for use in a turnover module in an embodiment in accordance with the invention. Turnbar 1000 can be used, for example, as stationary turnbars 500 shown in FIGS. 5-8. Turnbar 1000 includes an air-cushioned section 1002 in a portion of the perimeter of turnbar 1000. Air-cushioned section 1002 includes holes 1004 that are configured to allow pressurized air or gas to pass through the holes and cause the web to “float” over the air-cushioned section 1002. The remaining portion of the perimeter of turnbar 1000, identified herein as a friction section 1006, does not include any holes. The friction section 1006 includes a friction-inducing material affixed to or disposed over the entire friction section or a portion or portions of the friction section. The friction section 1006 is used to maintain web stability.

Air-cushioned section 1002 introduces a cushion of air or gas 1100 (FIG. 11) between the air-cushioned section and the web 1102. The web 1102 does not contact, or does not substantially contact the turnbar in the air-cushioned section but does contact the turnbar in the friction section 1006. The area of contact between the web 1102 and the friction section 1006 produces a sufficient amount of friction that reduces web tension without inducing web wander.

Although FIGS. 10 and 11 illustrate only one air-cushioned section, other embodiments in accordance with the invention can include more than one air-cushioned section. The air-cushioned sections can be arranged in any given pattern on the perimeter of the turnbar. By way of example only, two strips of air-cushioned sections can extend across the entire width of a turnbar with friction sections formed between the air-cushioned sections.

FIG. 12 illustrates a replaceable cover suitable for use with turnbar 1000 shown in FIG. 10 in an embodiment in accordance with the invention. Replaceable cover 1200 includes holes 1202. The locations of all of the holes 1202 in replaceable cover 1200 match the locations of the holes 1004 in the air-cushioned section 1002 in the turnbar 1000 in an embodiment in accordance with the invention. In another embodiment, the locations of only a portion of the holes 1202 in replaceable cover 1200 match the locations of the holes 1004 in the air-cushioned section 1002 in the turnbar 1000. Some of the holes 1004 in the air-cushioned section 1002 are blocked when only a portion of the holes 1202 match the locations of the holes 1004 in the air-cushioned section 1002, thereby allowing the amount of pressurized air or gas emitted from the air-cushioned section 1002 to be variable and customized for different types of webs.

The air-cushioned section 1002 can extend beyond the edge of the holes 1004 due to the exit path for the air. Depending on the configuration of the turnbar and width of the print media, the air-cushioned section may extend to the edges of the print media. The pattern of the holes 1202 in the replaceable cover 1200 can be adjusted to provide a full air-cushioned turnbar with minimum airflow requirements for different web widths.

FIGS. 13 and 14 depict one example of an S-wrap device and replaceable covers in an embodiment in accordance with the invention. S-wrap device 1300 includes two stationary bars 1302, 1304. Extending outward from each bar 1302, 1304 are pins 1306 (pins 1306 shown only on bar 1304 in FIG. 13). Disposed over a portion of each bar 1302, 1304 is a replaceable cover 1308 that connects or attaches over the bars 1302, 1304 with fastening systems 1310. Fastening systems 1310 are configured as the fastening systems 512 shown in FIGS. 5-7 in an embodiment in accordance with the invention.

As the web 1400 (see FIG. 13) is transported through the printing system, the web 1400 wraps around bars 1302, 1304 in an S configuration. As the web 1400 is pulled over the stationary surfaces of the bars 1302, 1304, the friction of the web 1400 across these surfaces produces tension in the web. As discussed earlier, an adjustment mechanism (not shown) can be connected to the bars 1302, 1304 to adjust the positional relationship between the stationary surfaces of the bars 1302, 1304 to control the angle of wrap and allow adjustments in the tension of the web 1400.

In prior art printing systems, a cover is not used with S-wrap devices because the function of the S-wrap devices is to create drag. However, certain cover materials can be advantageous for specific web materials. Providing a replaceable cover that is easy to install and remove enables use of an expanded range of web materials.

The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. And even though specific embodiments of the invention have been described herein, it should be noted that the application is not limited to these embodiments. In particular, any features described with respect to one embodiment may also be used in other embodiments, where compatible. The features of the different embodiments may be exchanged, where compatible.

1. A stationary bar for a web transport system in a printing system can include a first set of pins extending outward from an exterior surface of the bar; and a replaceable cover wrapped over at least a portion of the exterior surface of the bar, wherein the replaceable cover includes a plurality of openings at one end of the cover with openings positioned at locations of respective pins and a plurality of fasteners at another end of the cover each fastener adapted to removably attach the cover over the bar. 2. The bar as in clause 1, where each fastener is adapted to removably attach to a respective pin. 3. The bar as in clause 2, where the plurality of fasteners include springs. 4. The bar as in any one of clauses 1-3, where the bar includes a second set of pins extending outward from the exterior surface of the bar and positioned a given distance away from the first set of pins. 5. The bar in any one of clauses 1-4 can include a hollow center and a plurality of holes formed through the bar, where air or gas is emitted from the plurality of holes. 6. The bar as in clause 5, where the replaceable cover can include a plurality of holes formed through the replaceable cover, where locations of the plurality of holes through the replaceable cover correspond to locations of the plurality of holes formed through the bar. 7. The bar as in clause 5, where the replaceable cover can include a plurality of holes formed through the replaceable cover, where locations of a portion of the plurality of holes in the replaceable cover correspond to a respective portion of locations of the plurality of holes formed in the bar. 8. The bar as in any one of clauses 1-7, where the bar includes at least one of a turnbar in a turnover module and a bar in an S-wrap device. 9. The bar as in any one of clauses 1-8, where the replaceable cover is made of a material having a low coefficient of friction. 10. A web transport system in a printing system can include a plurality of bars for supporting a moving web; a first set of pins extending outward from an exterior surface of at least one bar in the plurality of bars; and a replaceable cover wrapped over at least a portion of the exterior surface of the at least one bar, wherein the replaceable cover includes a plurality of openings at one end of the cover with openings positioned at locations of respective pins, and wherein a plurality of fasteners are attached at another end of the cover with each fastener adapted to removably attach the cover over the bar. 11. The web transport system as in clause 10, where each fastener is adapted to removably attach to a respective pin. 12. The web transport system as in clause 11, where the plurality of fasteners includes springs. 13. The web transport system as in any one of clauses 10-12, where the at least one bar includes two turnbars disposed in a turnover module. 14. The web transport system as in clause 13, where each turnbar includes a second set of pins extending outward from the exterior surfaces of the turnbars and positioned a given distance away from the first set of pins. 15. The web transport system as in any one of clauses 10-14, where the at least one bar includes two bars disposed adjacent to one another in an S-wrap device. 16. The web transport system as in any one of clauses 10-15, where the replaceable cover is made of a material having a low coefficient of friction. 17. The web transport system as in any one of clauses 10-16, where the at least one bar further includes a hollow center and a plurality of holes formed through the bar, where air or gas is emitted from the plurality of holes. 18. The web transport system as in clause 17, where the replaceable cover can include a plurality of holes formed through the replaceable cover, where locations of the plurality of holes through the replaceable cover correspond to locations of the plurality of holes formed through the at least one bar. 19. The web transport system as in clause 17, where the replaceable cover can include a plurality of holes formed through the replaceable cover, where locations of a portion of the plurality of holes in the replaceable cover correspond to a respective portion of locations of the plurality of holes formed in the at least one bar. 20. The web transport system as in any one of clauses 10-19, where the replaceable cover is made of a material that is optimal for a particular type of web.

PARTS LIST

-   -   100 printing system     -   102 printing module     -   104 printing module     -   106 linehead     -   108 dryer     -   110 quality control sensor     -   112 print media     -   112 f front side of print media     -   112 b back side of print media     -   114 feed direction     -   116 turnover module     -   200 turnbar     -   202 turnbar     -   204 input path     -   206 output path     -   208 unit     -   210 region     -   212 region     -   214 roller     -   300 roller     -   500 turnbar     -   502 mounting bracket     -   504 hole     -   506 pin     -   508 exterior surface of turnbar     -   510 replaceable cover     -   512 fastening system     -   514 first set of openings     -   516 second set of openings     -   518 fastener     -   600 beam     -   602 beam     -   800 turnover module     -   900 fastening system     -   902 pin     -   1000 turnbar     -   1002 air-cushioned section     -   1004 holes     -   1006 friction section     -   1100 cushion of air     -   1102 web     -   1200 replaceable cover     -   1202 holes     -   1300 S-wrap device     -   1302 bar     -   1304 bar     -   1306 pin     -   1308 replaceable cover     -   1310 fastening system     -   1400 web     -   A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P Rollers     -   SW S-wrap 

1. A stationary bar for a web transport system in a printing system, comprising: a first set of pins extending outward from an exterior surface of the bar; and a replaceable cover wrapped over at least a portion of the exterior surface of the bar, wherein the replaceable cover includes a plurality of openings at one end of the cover with openings positioned at locations of respective pins and a plurality of fasteners at another end of the cover each fastener adapted to removably attach the cover over the bar.
 2. The bar as in claim 1, wherein each fastener is adapted to removably attach to a respective pin.
 3. The bar as in claim 2, wherein the plurality of fasteners comprises springs.
 4. The bar as in claim 1, wherein the bar comprises at least one of a turnbar in a turnover module and a bar in an S-wrap device.
 5. The bar as in claim 1, wherein the bar comprises a second set of pins extending outward from the exterior surface of the bar and positioned a given distance away from the first set of pins.
 6. The bar as in claim 1, wherein the replaceable cover is made of a material having a low coefficient of friction.
 7. The bar as in claim 1, wherein the bar further includes a hollow center and a plurality of holes formed through the bar, wherein air or gas is emitted from the plurality of holes.
 8. The bar as in claim 7, wherein the replaceable cover further includes a plurality of holes formed through the replaceable cover, wherein locations of the plurality of holes through the replaceable cover correspond to locations of the plurality of holes formed through the bar.
 9. The bar as in claim 7, wherein the replaceable cover further includes a plurality of holes formed through the replaceable cover, wherein locations of a portion of the plurality of holes in the replaceable cover correspond to a respective portion of locations of the plurality of holes formed in the bar.
 10. A web transport system in a printing system, comprising: a plurality of bars for supporting a moving web; a first set of pins extending outward from an exterior surface of at least one stationary bar in the plurality of bars; and a replaceable cover wrapped over at least a portion of the exterior surface of the at least one bar, wherein the replaceable cover includes a plurality of openings at one end of the cover with openings positioned at locations of respective pins, and wherein a plurality of fasteners are attached at another end of the cover with each fastener adapted to removably attach the cover over the bar.
 11. The web transport system as in claim 10, wherein each fastener is adapted to removably attach to a respective pin.
 12. The web transport system as in claim 11, wherein the plurality of fasteners comprises springs.
 13. The web transport system as in claim 10, wherein the at least one bar comprises two turnbars disposed in a turnover module.
 14. The web transport system as in claim 13, wherein each turnbar includes a second set of pins extending outward from the exterior surfaces of the turnbars and positioned a given distance away from the first set of pins.
 15. The web transport system as in claim 10, wherein the at least one bar comprises two bars disposed adjacent to one another in an S-wrap device.
 16. The web transport system as in claim 10, wherein the replaceable cover is made of a material having a low coefficient of friction.
 17. The web transport system as in claim 10, wherein the at least one bar further includes a hollow center and a plurality of holes formed through the bar, wherein air or gas is emitted from the plurality of holes.
 18. The web transport system as in claim 17, wherein the replaceable cover further includes a plurality of holes formed through the replaceable cover, wherein locations of the plurality of holes through the replaceable cover correspond to locations of the plurality of holes formed through the at least one bar.
 19. The web transport system as in claim 17, wherein the replaceable cover further includes a plurality of holes formed through the replaceable cover, wherein locations of a portion of the plurality of holes in the replaceable cover correspond to a respective portion of locations of the plurality of holes formed in the at least one bar.
 20. The web transport system as in claim 10, wherein the replaceable cover is made of a material that is optimal for a particular type of web. 